Neurotrophin receptor homolog (NRH1) proteins regulate mesoderm formation and apoptosis during early Xenopus development

In Vivo and Explant Electroporation of Morpholinos in the Developing Mouse Retina

Neonatal in vivo electroporations and retinal explant electroporations have been widely employed in understanding the effects of loss or gain of function of protein-coding genes in retinal development. Here, we describe a rapid and efficient delivery of morpholinos to add another tool to perturb gene expression during mouse retinal development.

Novel Genes Critical for Hypoxic Preconditioning in Zebrafish Are Regulators of Insulin and Glucose Metabolism

Severe hypoxia is a common cause of major brain, heart, and kidney injury in adults, children, and newborns. However, mild hypoxia can be protective against later, more severe hypoxia exposure via "hypoxic preconditioning," a phenomenon that is not yet fully understood. Accordingly, we have established and optimized an embryonic zebrafish model to study hypoxic preconditioning. Using a functional genomic approach, we used this zebrafish model to identify and validate five novel hypoxia-protective genes, including irs2, crtc3, and camk2g2, which have been previously implicated in metabolic regulation. These results extend our understanding of the mechanisms of hypoxic preconditioning and affirm the discovery potential of this novel vertebrate hypoxic stress model.

Dock3 induces axonal outgrowth by stimulating membrane recruitment of the WAVE complex

Atypical Rho-guanine nucleotide exchange factors (Rho-GEFs) that contain Dock homology regions (DHR-1 and DHR-2) are expressed in a variety of tissues; however, their functions and mechanisms of action remain unclear. We identify key conserved amino acids in the DHR-2 domain that are critical for the catalytic activity of Dock-GEFs (Dock1-4). We further demonstrate that Dock-GEFs directly associate with WASP family verprolin-homologous (WAVE) proteins through the DHR-1 domain. Brain-derived neurotrophic factor (BDNF)-TrkB signaling recruits the Dock3/WAVE1 complex to the plasma membrane, whereupon Dock3 activates Rac and dissociates from the WAVE complex in a phosphorylation-dependent manner. BDNF induces axonal sprouting through Dock-dependent Rac activation, and adult transgenic mice overexpressing Dock3 exhibit enhanced optic nerve regeneration after injury without affecting WAVE expression levels. Our results highlight a unique mechanism through which Dock-GEFs achieve spatial and temporal restriction of WAVE signaling, and identify Dock-GEF activity as a potential therapeutic target for axonal regeneration.

Controlling morpholino experiments: don't stop making antisense

One of the most significant problems facing developmental biologists who do not work on an organism with well-developed genetics - and even for some who do - is how to inhibit the action of a gene of interest during development so as to learn about its normal biological function. A widely adopted approach is to use antisense technologies, and especially morpholino antisense oligonucleotides. In this article, we review the use of such reagents and present examples of how they have provided insights into developmental mechanisms. We also discuss how the use of morpholinos can lead to misleading results, including off-target effects, and we suggest controls that will allow researchers to interpret morpholino experiments correctly.